linux/drivers/base/cpu.c
Frederic Weisbecker 04d4e665a6 sched/isolation: Use single feature type while referring to housekeeping cpumask
Refer to housekeeping APIs using single feature types instead of flags.
This prevents from passing multiple isolation features at once to
housekeeping interfaces, which soon won't be possible anymore as each
isolation features will have their own cpumask.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Reviewed-by: Phil Auld <pauld@redhat.com>
Link: https://lore.kernel.org/r/20220207155910.527133-5-frederic@kernel.org
2022-02-16 15:57:55 +01:00

614 lines
15 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* CPU subsystem support
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/cpu.h>
#include <linux/topology.h>
#include <linux/device.h>
#include <linux/node.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/percpu.h>
#include <linux/acpi.h>
#include <linux/of.h>
#include <linux/cpufeature.h>
#include <linux/tick.h>
#include <linux/pm_qos.h>
#include <linux/sched/isolation.h>
#include "base.h"
static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
static int cpu_subsys_match(struct device *dev, struct device_driver *drv)
{
/* ACPI style match is the only one that may succeed. */
if (acpi_driver_match_device(dev, drv))
return 1;
return 0;
}
#ifdef CONFIG_HOTPLUG_CPU
static void change_cpu_under_node(struct cpu *cpu,
unsigned int from_nid, unsigned int to_nid)
{
int cpuid = cpu->dev.id;
unregister_cpu_under_node(cpuid, from_nid);
register_cpu_under_node(cpuid, to_nid);
cpu->node_id = to_nid;
}
static int cpu_subsys_online(struct device *dev)
{
struct cpu *cpu = container_of(dev, struct cpu, dev);
int cpuid = dev->id;
int from_nid, to_nid;
int ret;
from_nid = cpu_to_node(cpuid);
if (from_nid == NUMA_NO_NODE)
return -ENODEV;
ret = cpu_device_up(dev);
/*
* When hot adding memory to memoryless node and enabling a cpu
* on the node, node number of the cpu may internally change.
*/
to_nid = cpu_to_node(cpuid);
if (from_nid != to_nid)
change_cpu_under_node(cpu, from_nid, to_nid);
return ret;
}
static int cpu_subsys_offline(struct device *dev)
{
return cpu_device_down(dev);
}
void unregister_cpu(struct cpu *cpu)
{
int logical_cpu = cpu->dev.id;
unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
device_unregister(&cpu->dev);
per_cpu(cpu_sys_devices, logical_cpu) = NULL;
return;
}
#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
static ssize_t cpu_probe_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
ssize_t cnt;
int ret;
ret = lock_device_hotplug_sysfs();
if (ret)
return ret;
cnt = arch_cpu_probe(buf, count);
unlock_device_hotplug();
return cnt;
}
static ssize_t cpu_release_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t count)
{
ssize_t cnt;
int ret;
ret = lock_device_hotplug_sysfs();
if (ret)
return ret;
cnt = arch_cpu_release(buf, count);
unlock_device_hotplug();
return cnt;
}
static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
#endif /* CONFIG_HOTPLUG_CPU */
struct bus_type cpu_subsys = {
.name = "cpu",
.dev_name = "cpu",
.match = cpu_subsys_match,
#ifdef CONFIG_HOTPLUG_CPU
.online = cpu_subsys_online,
.offline = cpu_subsys_offline,
#endif
};
EXPORT_SYMBOL_GPL(cpu_subsys);
#ifdef CONFIG_KEXEC
#include <linux/kexec.h>
static ssize_t crash_notes_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct cpu *cpu = container_of(dev, struct cpu, dev);
unsigned long long addr;
int cpunum;
cpunum = cpu->dev.id;
/*
* Might be reading other cpu's data based on which cpu read thread
* has been scheduled. But cpu data (memory) is allocated once during
* boot up and this data does not change there after. Hence this
* operation should be safe. No locking required.
*/
addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
return sysfs_emit(buf, "%llx\n", addr);
}
static DEVICE_ATTR_ADMIN_RO(crash_notes);
static ssize_t crash_notes_size_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sysfs_emit(buf, "%zu\n", sizeof(note_buf_t));
}
static DEVICE_ATTR_ADMIN_RO(crash_notes_size);
static struct attribute *crash_note_cpu_attrs[] = {
&dev_attr_crash_notes.attr,
&dev_attr_crash_notes_size.attr,
NULL
};
static const struct attribute_group crash_note_cpu_attr_group = {
.attrs = crash_note_cpu_attrs,
};
#endif
static const struct attribute_group *common_cpu_attr_groups[] = {
#ifdef CONFIG_KEXEC
&crash_note_cpu_attr_group,
#endif
NULL
};
static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
#ifdef CONFIG_KEXEC
&crash_note_cpu_attr_group,
#endif
NULL
};
/*
* Print cpu online, possible, present, and system maps
*/
struct cpu_attr {
struct device_attribute attr;
const struct cpumask *const map;
};
static ssize_t show_cpus_attr(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
return cpumap_print_to_pagebuf(true, buf, ca->map);
}
#define _CPU_ATTR(name, map) \
{ __ATTR(name, 0444, show_cpus_attr, NULL), map }
/* Keep in sync with cpu_subsys_attrs */
static struct cpu_attr cpu_attrs[] = {
_CPU_ATTR(online, &__cpu_online_mask),
_CPU_ATTR(possible, &__cpu_possible_mask),
_CPU_ATTR(present, &__cpu_present_mask),
};
/*
* Print values for NR_CPUS and offlined cpus
*/
static ssize_t print_cpus_kernel_max(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%d\n", NR_CPUS - 1);
}
static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
unsigned int total_cpus;
static ssize_t print_cpus_offline(struct device *dev,
struct device_attribute *attr, char *buf)
{
int len = 0;
cpumask_var_t offline;
/* display offline cpus < nr_cpu_ids */
if (!alloc_cpumask_var(&offline, GFP_KERNEL))
return -ENOMEM;
cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
len += sysfs_emit_at(buf, len, "%*pbl", cpumask_pr_args(offline));
free_cpumask_var(offline);
/* display offline cpus >= nr_cpu_ids */
if (total_cpus && nr_cpu_ids < total_cpus) {
len += sysfs_emit_at(buf, len, ",");
if (nr_cpu_ids == total_cpus-1)
len += sysfs_emit_at(buf, len, "%u", nr_cpu_ids);
else
len += sysfs_emit_at(buf, len, "%u-%d",
nr_cpu_ids, total_cpus - 1);
}
len += sysfs_emit_at(buf, len, "\n");
return len;
}
static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
static ssize_t print_cpus_isolated(struct device *dev,
struct device_attribute *attr, char *buf)
{
int len;
cpumask_var_t isolated;
if (!alloc_cpumask_var(&isolated, GFP_KERNEL))
return -ENOMEM;
cpumask_andnot(isolated, cpu_possible_mask,
housekeeping_cpumask(HK_TYPE_DOMAIN));
len = sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(isolated));
free_cpumask_var(isolated);
return len;
}
static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
#ifdef CONFIG_NO_HZ_FULL
static ssize_t print_cpus_nohz_full(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
}
static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
#endif
static void cpu_device_release(struct device *dev)
{
/*
* This is an empty function to prevent the driver core from spitting a
* warning at us. Yes, I know this is directly opposite of what the
* documentation for the driver core and kobjects say, and the author
* of this code has already been publically ridiculed for doing
* something as foolish as this. However, at this point in time, it is
* the only way to handle the issue of statically allocated cpu
* devices. The different architectures will have their cpu device
* code reworked to properly handle this in the near future, so this
* function will then be changed to correctly free up the memory held
* by the cpu device.
*
* Never copy this way of doing things, or you too will be made fun of
* on the linux-kernel list, you have been warned.
*/
}
#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
static ssize_t print_cpu_modalias(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int len = 0;
u32 i;
len += sysfs_emit_at(buf, len,
"cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
CPU_FEATURE_TYPEVAL);
for (i = 0; i < MAX_CPU_FEATURES; i++)
if (cpu_have_feature(i)) {
if (len + sizeof(",XXXX\n") >= PAGE_SIZE) {
WARN(1, "CPU features overflow page\n");
break;
}
len += sysfs_emit_at(buf, len, ",%04X", i);
}
len += sysfs_emit_at(buf, len, "\n");
return len;
}
static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
{
char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
if (buf) {
print_cpu_modalias(NULL, NULL, buf);
add_uevent_var(env, "MODALIAS=%s", buf);
kfree(buf);
}
return 0;
}
#endif
/*
* register_cpu - Setup a sysfs device for a CPU.
* @cpu - cpu->hotpluggable field set to 1 will generate a control file in
* sysfs for this CPU.
* @num - CPU number to use when creating the device.
*
* Initialize and register the CPU device.
*/
int register_cpu(struct cpu *cpu, int num)
{
int error;
cpu->node_id = cpu_to_node(num);
memset(&cpu->dev, 0x00, sizeof(struct device));
cpu->dev.id = num;
cpu->dev.bus = &cpu_subsys;
cpu->dev.release = cpu_device_release;
cpu->dev.offline_disabled = !cpu->hotpluggable;
cpu->dev.offline = !cpu_online(num);
cpu->dev.of_node = of_get_cpu_node(num, NULL);
#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
cpu->dev.bus->uevent = cpu_uevent;
#endif
cpu->dev.groups = common_cpu_attr_groups;
if (cpu->hotpluggable)
cpu->dev.groups = hotplugable_cpu_attr_groups;
error = device_register(&cpu->dev);
if (error) {
put_device(&cpu->dev);
return error;
}
per_cpu(cpu_sys_devices, num) = &cpu->dev;
register_cpu_under_node(num, cpu_to_node(num));
dev_pm_qos_expose_latency_limit(&cpu->dev,
PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);
return 0;
}
struct device *get_cpu_device(unsigned int cpu)
{
if (cpu < nr_cpu_ids && cpu_possible(cpu))
return per_cpu(cpu_sys_devices, cpu);
else
return NULL;
}
EXPORT_SYMBOL_GPL(get_cpu_device);
static void device_create_release(struct device *dev)
{
kfree(dev);
}
__printf(4, 0)
static struct device *
__cpu_device_create(struct device *parent, void *drvdata,
const struct attribute_group **groups,
const char *fmt, va_list args)
{
struct device *dev = NULL;
int retval = -ENOMEM;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
goto error;
device_initialize(dev);
dev->parent = parent;
dev->groups = groups;
dev->release = device_create_release;
device_set_pm_not_required(dev);
dev_set_drvdata(dev, drvdata);
retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
if (retval)
goto error;
retval = device_add(dev);
if (retval)
goto error;
return dev;
error:
put_device(dev);
return ERR_PTR(retval);
}
struct device *cpu_device_create(struct device *parent, void *drvdata,
const struct attribute_group **groups,
const char *fmt, ...)
{
va_list vargs;
struct device *dev;
va_start(vargs, fmt);
dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs);
va_end(vargs);
return dev;
}
EXPORT_SYMBOL_GPL(cpu_device_create);
#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
#endif
static struct attribute *cpu_root_attrs[] = {
#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
&dev_attr_probe.attr,
&dev_attr_release.attr,
#endif
&cpu_attrs[0].attr.attr,
&cpu_attrs[1].attr.attr,
&cpu_attrs[2].attr.attr,
&dev_attr_kernel_max.attr,
&dev_attr_offline.attr,
&dev_attr_isolated.attr,
#ifdef CONFIG_NO_HZ_FULL
&dev_attr_nohz_full.attr,
#endif
#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
&dev_attr_modalias.attr,
#endif
NULL
};
static const struct attribute_group cpu_root_attr_group = {
.attrs = cpu_root_attrs,
};
static const struct attribute_group *cpu_root_attr_groups[] = {
&cpu_root_attr_group,
NULL,
};
bool cpu_is_hotpluggable(unsigned int cpu)
{
struct device *dev = get_cpu_device(cpu);
return dev && container_of(dev, struct cpu, dev)->hotpluggable;
}
EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
#ifdef CONFIG_GENERIC_CPU_DEVICES
static DEFINE_PER_CPU(struct cpu, cpu_devices);
#endif
static void __init cpu_dev_register_generic(void)
{
#ifdef CONFIG_GENERIC_CPU_DEVICES
int i;
for_each_possible_cpu(i) {
if (register_cpu(&per_cpu(cpu_devices, i), i))
panic("Failed to register CPU device");
}
#endif
}
#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
ssize_t __weak cpu_show_meltdown(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "Not affected\n");
}
ssize_t __weak cpu_show_spectre_v1(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "Not affected\n");
}
ssize_t __weak cpu_show_spectre_v2(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "Not affected\n");
}
ssize_t __weak cpu_show_spec_store_bypass(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "Not affected\n");
}
ssize_t __weak cpu_show_l1tf(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "Not affected\n");
}
ssize_t __weak cpu_show_mds(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "Not affected\n");
}
ssize_t __weak cpu_show_tsx_async_abort(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sysfs_emit(buf, "Not affected\n");
}
ssize_t __weak cpu_show_itlb_multihit(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "Not affected\n");
}
ssize_t __weak cpu_show_srbds(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "Not affected\n");
}
static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL);
static struct attribute *cpu_root_vulnerabilities_attrs[] = {
&dev_attr_meltdown.attr,
&dev_attr_spectre_v1.attr,
&dev_attr_spectre_v2.attr,
&dev_attr_spec_store_bypass.attr,
&dev_attr_l1tf.attr,
&dev_attr_mds.attr,
&dev_attr_tsx_async_abort.attr,
&dev_attr_itlb_multihit.attr,
&dev_attr_srbds.attr,
NULL
};
static const struct attribute_group cpu_root_vulnerabilities_group = {
.name = "vulnerabilities",
.attrs = cpu_root_vulnerabilities_attrs,
};
static void __init cpu_register_vulnerabilities(void)
{
if (sysfs_create_group(&cpu_subsys.dev_root->kobj,
&cpu_root_vulnerabilities_group))
pr_err("Unable to register CPU vulnerabilities\n");
}
#else
static inline void cpu_register_vulnerabilities(void) { }
#endif
void __init cpu_dev_init(void)
{
if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
panic("Failed to register CPU subsystem");
cpu_dev_register_generic();
cpu_register_vulnerabilities();
}